Evaluation method

ABSTRACT

An evaluation method is a method for evaluating a charging connector in coolability by connecting an evaluation jig to the charging connector, the charging connector including a pair of male terminals coolable with a coolant, the evaluation jig including a pair of female terminals, the pair of female terminals being connected to the pair of male terminals in evaluating the charging connector in coolability. The method comprises: connecting the pair of female terminals to the pair of male terminals; adjusting a connection state between the male terminal and the female terminal such that contact resistance between the terminals is 0.06 mΩ or more and 0.15 mΩ or less; and after the adjusting, evaluating the coolability depending on whether the male and female terminals have a temperature of 90° C. or lower when a charging current of 400 A is supplied to the terminals for 30 minutes.

This nonprovisional application is based on Japanese Patent ApplicationNo. 2020-003138 filed on Jan. 10, 2020 with the Japan Patent Office, theentire contents of which are hereby incorporated by reference.

BACKGROUND Field

The present disclosure relates to an evaluation method.

Description of the Background Art

A connecting portion of a charging connector on the side of facilitiesand a charging inlet on the side of a vehicle generates heat due tocontact resistance when a current passes therethrough. This isparticularly remarkable when rapid charging is performed with a largecurrent (for example of 400 A). Accordingly, a liquid-cooled typecharging connector coolable with liquid such as water is known. Forexample, Japanese Patent Laying-Open No. 2019-187035 discloses aliquid-cooled type charging connector comprising a connector connectableto a vehicular inlet and a cooling mechanism capable of cooling theconnector with a coolant (or cooling water).

SUMMARY

When such a liquid-cooled charging connector as disclosed in JapanesePatent Laying-Open No. 2019-187035 varies in coolability, it affects aperiod of time taken to charge power. For example, a charging connectorwith relatively low coolability requires a longer charging time.Therefore, there is a need for appropriately evaluating a chargingconnector in coolability.

An object of the present disclosure is to provide an evaluation methodcapable of appropriately evaluating a charging connector in coolability.

In order to address the above issue, an evaluation jig comprising a pairof female terminals connectable to a pair of male terminals of acharging connector may be used to evaluate the charging connector incoolability (or a degree at which temperature increases at a connectingportion of the male terminal and the female terminal).

If the contact resistance between the male terminal and the femaleterminal when an evaluation is made varies whenever the evaluation ismade, the evaluation provides an unreliable result. Therefore, it isdesirable that coolability be evaluated while the contact resistancefalls within a prescribed range. The present disclosure has been madebased on the above point of view.

According to one aspect of the present disclosure, an evaluation methodis an evaluation method for evaluating a charging connector incoolability by connecting an evaluation jig to the charging connector,the charging connector including a pair of male terminals coolable witha coolant, the evaluation jig including a pair of female terminalsconnectable to the pair of male terminals, the pair of female terminalsbeing connected to the pair of male terminals in evaluating the chargingconnector in coolability, the method comprising: connecting the pair offemale terminals to the pair of male terminals; adjusting a connectionstate between the male terminal and the female terminal such thatcontact resistance between the male terminal and the female terminal is0.06 mΩ or more and 0.15 mΩ or less; and after the adjusting theconnection state, evaluating the coolability depending on whether themale terminal and the female terminal have a temperature of 90° C. orlower when a charging current of 400 A is supplied to the male terminaland the female terminal for 30 minutes.

In the present evaluation method, contact resistance between the maleterminal and the female terminal is defined to fall within a range of0.06 mΩ or more and 0.15 mΩ or less, and variation in evaluation resultsis suppressed. Therefore, the charging connector's coolability can beappropriately evaluated. Further, designing the female terminal of thecharging inlet such that the contact resistance is 0.06 mΩ or more and0.15 mΩ or less allows the male terminal and the female terminal to havea temperature of 90° C. or lower when a charging connector which obtainsa good evaluation result in the step of evaluating is used to chargepower with a charging current of 400 A supplied for 30 minutes.

Furthermore, in the adjusting the connection state, the connection stateis preferably adjusted so that the contact resistance is 0.08 mΩ or moreand 0.1 mΩ or less.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing a vehicle charged.

FIG. 2 is a front view of a male connector.

FIG. 3 is a cross section taken along a line indicated in FIG. 2.

FIG. 4 is a perspective view of an evaluation jig according to anembodiment of the present disclosure.

FIG. 5 is a perspective view in a vicinity of a female terminal of theevaluation jig.

FIG. 6 is a perspective view showing a relationship between the femaleterminal of the evaluation jig and an adjustment member.

FIG. 7 is a plan view of the female terminal of the evaluation jig.

FIG. 8 is a perspective view of the female terminal shown in FIG. 7.

FIG. 9 is a perspective view of the female terminal at an angledifferent from that of FIG. 8.

FIG. 10 is an enlarged perspective view of a distal end portion of thefemale terminal.

FIG. 11 is a cross section taken along a line XI-XI shown in FIG. 7.

FIG. 12 is a cross section taken along a line XII-XII shown in FIG. 7.

FIG. 13 is an enlarged view of a range indicated by a solid line XIIIshown in FIG. 12.

FIG. 14 is a front view of a male connector having a tubular wallpartially removed.

FIG. 15 is a perspective view of the male connector shown in FIG. 14.

FIG. 16 is a cross section taken along a line XVI-XVI indicated in FIG.14.

FIG. 17 is a perspective view showing a state in which the evaluationjig has a female terminal connected to a male terminal of the maleconnector shown in FIG. 15.

FIG. 18 is a cross section of the diagram shown in FIG. 17.

FIG. 19 is a diagram schematically showing a degree at which temperaturerises at each portion around a connecting portion of a male terminal anda female terminal.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An Embodiment of the present disclosure will be described with referenceto the drawings. In the drawings referred to below, identical orequivalent members are identically denoted.

FIG. 1 is a diagram schematically showing a vehicle charged. Morespecifically, FIG. 1 shows a state in which a charging connector 5connected to a facility 7 such as a charging stand via a facility-sideelectric wire 6 is connected to a charging inlet 2 of a vehicle 1.Vehicle 1 is, for example, an electric vehicle.

Charging connector 5 includes a handle (not shown) held by a user, and amale connector 10 (see FIG. 2) connected to the handle. Chargingconnector 5 is cooled by a coolant. That is, charging connector 5 is aso-called liquid-cooled charging connector. An example of the coolantincludes cooling water. The coolant flows between facility 7 andcharging connector 5 via facility-side electric wire 6.

Male connector 10 is a portion connected to charging inlet 2 of vehicle1. In the present embodiment, male connector 10 is based on the ChaoJistandard. As shown in FIG. 2, male connector 10 includes a pair of maleterminals 11, a protective grounding terminal 12, a pair of chargingconnection confirmation terminals 13, a pair of charging communicationterminals 14, and a male casing 15.

Each male terminal 11 is formed in a round column. Each male terminal 11is a direct-current power supply terminal. One male terminal 11 is apositive electrode and the other male terminal 11 is a negativeelectrode. In the present embodiment, male terminal 11 has an outerdiameter of 9 mm.

Protective grounding terminal 12 is disposed at a position spaced from acenter portion between the paired male terminals 11 on one side in adirection orthogonal to both an imaginary line connecting the pairedmale terminals 11 (i.e., a lateral direction in FIG. 2) and an axis ofeach male terminals 11, that is, in a vertical direction in FIG. 2.

Each charging connection confirmation terminal 13 is disposed at aposition spaced from one male terminal 11 on one side in the orthogonaldirection.

Each charging communication terminal 14 is disposed at a position spacedfrom the other male terminal 11 on one side in the orthogonal directionand also spaced from each charging connection confirmation terminal 13in a direction parallel to the imaginary line connecting the paired maleterminals 11.

Male casing 15 holds terminals 11 to 14. Male casing 15 is made ofresin. Male casing 15 has a bottom wall 16 and a tubular wall 17.

As shown in FIG. 3, bottom wall 16 holds terminals 11 to 14 in a statein which terminals 11 to 14 are inserted therethrough. Bottom wall 16 isformed in a flat plate. FIG. 3 shows a part of female connector 20 ofcharging inlet 2.

Tubular wall 17 surrounds male terminal 11. Tubular wall 17 erects froma portion of bottom wall 16 around male terminal 11. Tubular wall 17 hasa cylindrical inner peripheral surface. Female connector 20 of charginginlet 2 is inserted into a space between the inner peripheral surfaceand an outer peripheral surface of male terminal 11. As shown in FIG. 3,tubular wall 17 has an inner diameter set to 23 mm.

Charging inlet 2 is provided on an external surface of vehicle 1.Charging inlet 2 includes female connector 20. Female connector 20 has apair of female terminals 21 and a female casing 25.

Each female terminal 21 is connectable to male terminal 11. As shown inFIG. 3, each female terminal 21 has a shape capable of receiving maleterminal 11.

Female casing 25 holds female terminals 21. Female casing 25 is made ofresin. As shown in FIG. 3, female casing 25 has a facing portion 26 anda tubular portion 27.

Facing portion 26 is a portion facing tubular wall 17 in a directionparallel to the axial direction of male terminal 11 (i.e., a verticaldirection in FIG. 3). Facing portion 26 has a surface 26S formed flat.As shown in FIG. 3, a distance between surface 26S of facing portion 26and a surface 16S of bottom wall 16 in the direction parallel to theaxial direction of male terminal 11 is set to 40 mm.

Tubular portion 27 is formed to have a cylindrical shape surroundingfemale terminal 21. Tubular portion 27 is connected to facing portion 26in a posture such that tubular portion 27 has its center axis orthogonalto facing portion 26. Tubular portion 27 has an outer diameter smallerthan the inner diameter of tubular wall 17. In a state with chargingconnector 5 connected to charging inlet 2, tubular portion 27 has adistal end portion 27 a in contact with surface 16S of bottom wall 16.As shown in FIG. 3, distal end portion 27 a has a length set to 6 mm ina direction parallel to the axial direction of tubular portion 27.

Hereinafter, evaluation jig 50 will be described with reference to FIGS.4 to 13. Evaluation jig 50 is a jig capable of evaluating chargingconnector 5 in coolability (or amount of heat generated at a connectingportion of male terminal 11 and the female terminal). As shown in FIG.4, evaluation jig 50 includes a pair of female terminals 100, anelectric wire 200, a pair of crimp terminals 300, and a pair ofadjustment members 400.

Each female terminal 100 is a terminal connected to male terminal 11.Each female terminal 100 includes a plurality of (eight in the presentembodiment) contact pieces 110, a support portion 120, and a female-sideflange 130.

Each contact piece 110 is a portion that can contact male terminal 11.The plurality of contact pieces 110 are disposed about and spaced from acenter axis A (see FIGS. 11 to 13). Specifically, the plurality ofcontact pieces 110 are disposed about and equally spaced from centeraxis A. Contact pieces 110 are preferably set in number to 3 or more and8 or less, particularly preferably 8. Each contact piece 110 has aflexible piece 112 and a contact portion 114.

Flexible piece 112 has a shape extending in a direction parallel tocenter axis A. Flexible piece 112 forms a portion of a cylinder havingcenter axis A. In other words, in the cross sections shown in FIGS. 12and 13, flexible piece 112 has an outer peripheral surface in the formof an arc. A slit 112S is provided between any pair of flexible pieces112 adjacent in the circumferential direction of the cylinder.

In the direction parallel to center axis A, flexible piece 112 has alength L1 (see FIG. 7) set to be equal to or larger than twice the outerdiameter of the cylinder. In the present embodiment, the cylinder has anouter diameter φ2 (see FIG. 11) of 17 mm, and flexible piece 112 haslength L1 of 35 mm. The cylinder has an inner diameter φ1 (see FIG. 11)of 13 mm. That is, flexible piece 112 has a thickness of 2 mm.

Flexible piece 112 is elastically deformable such that flexible piece112 has a distal end portion 112 a displaced in the radial direction ofthe cylinder relative to a proximal end portion of flexible piece 112,which is a connecting portion of flexible piece 112 and support portion120. That is, the plurality of contact pieces 110 (the cylinder) can bereduced in diameter.

As shown in FIGS. 12 and 13, flexible piece 112 has a facing surface 112b facing flexible piece 112 adjacent to flexible piece 112 of interestin the circumferential direction of the cylinder. Any pair of facingsurfaces 112 b facing each other in the circumferential direction areparallel to each other. The paired facing surfaces 112 b are spaced by 1mm.

Contact portion 114 has a shape protruding from the inner surface offlexible piece 112 toward center axis A. Contact portion 114 isconnected to the inner surface of flexible piece 112 at a portion awayfrom distal end portion 112 a in the direction parallel to center axisA. That is, distal end portion 112 a of flexible piece 112 configures aprotruding portion protruding from contact portion 114 in the directionparallel to center axis A away from support portion 120 (or downward inFIG. 11).

Contact portion 114 has a shape curved so as to protrude inward in theradial direction. As shown in FIG. 13, flexible piece 112 and contactportion 114 have a boundary portion 113 therebetween in a curve. Contactportion 114 has an apex 114 c with a curvature smaller than that ofboundary portion 113. In the present embodiment, apex 114 c has a radiusof curvature of 1 mm. Boundary portion 113 has a radius of curvature forexample of 0.5 mm.

As shown in FIG. 13, a straight line connecting a specific apex 114 cand center axis A and a straight line connecting an apex 114 c adjacentto the specific apex 114 c and center axis A form an angle of 45degrees. A tangent to an end on one side of contact portion 114 in thecircumferential direction and a tangent to an end on the other side ofcontact portion 114 in the circumferential direction form an angle of 30degrees.

Contact portion 114 has a shape extending in the direction parallel tocenter axis A. As shown in FIGS. 10 and 11, contact portion 114 has acontact edge portion 114 a and a connecting portion 114 b.

Contact portion 114 has a shape extending in the direction parallel tocenter axis A. Contact edge portion 114 a has a length L3 of 4.7 mm.

Connecting portion 114 b connects contact edge portion 114 a and aninner surface of flexible piece 112. Connecting portion 114 b has ashape inclined so as to gradually approach the inner surface of flexiblepiece 112 as connecting portion 114 b is farther away from contact edgeportion 114 a in the direction parallel to center axis A. Connectingportion 114 b and the inner surface of flexible piece 112 have aboundary portion therebetween with a radius of curvature of 0.5 mm.Connecting portion 114 b and contact edge portion 114 a have a boundaryportion therebetween with a radius of curvature of 1.5 mm.

Support portion 120 supports the plurality of contact pieces 110. In thepresent embodiment, support portion 120 is formed to have a cylindricalshape having center axis A as a center. Support portion 120 has an outerperipheral surface contiguous to that of each flexible piece 112. Thatis, support portion 120 has an outer diameter equal to that of thecylinder composed of the plurality of flexible pieces 112.

As shown in FIG. 11, support portion 120 is equal in thickness to eachflexible piece 112. As shown in FIG. 7, in a direction along center axisA, support portion 120 has a length L2 set to be smaller than length L1of each flexible piece 112. Specifically, support portion 120 has lengthL2 of 22 mm. Support portion 120 may be formed in a round columnarshape, a rectangular columnar shape, or the like.

Female-side flange 130 has a shape projecting from an outer peripheralsurface of support portion 120 outward in the radial direction ofsupport portion 120. Female-side flange 130 is formed flat. In thedirection parallel to center axis A, female-side flange 130 has a lengthequal to that of support portion 120 (22 mm in the present embodiment).

Female-side flange 130 is provided with an insertion hole 130 h.Insertion hole 130 h has a diameter of 10.5 mm. A distance betweencenter axis A and the center of insertion hole 130 h is 21 mm.

Electric wire 200 is provided to connect the paired female terminals 100to each other. Electric wire 200 is made of copper or silver. Electricwire 200 preferably has a cross-sectional area set to 70 mm² or more and95 mm² or less. In the present embodiment, electric wire 200 has across-sectional area set to 95 mm². Electric wire 200 has a length setto 2 m or more. The reason for this will be described with reference toFIG. 19.

FIG. 19 represents each terminal and each electric wire in temperaturewhen male terminal 11 is connected to female terminal 21 and a currentof 400 A is supplied for 30 minutes. In FIG. 19, a region R of aconnecting portion of male terminal 11 and female terminal 21 is aregion which attains highest temperature.

As shown in FIG. 19, when a vehicle-side electric wire 3 has across-sectional area of 95 mm², and whether a portion up to 100 cm frommale terminal 11 may or may not be cooled with water, it has beenconfirmed that a portion of vehicle-side electric wire 3 away fromfemale terminal 21 by 100 cm is stable in temperature (or an effect ofheat generated at the connecting portion of male terminal 11 and femaleterminal 21 is substantially negligible).

Furthermore, when the portion is water-cooled, and whether vehicle-sideelectric wire 3 may have a cross-sectional area of 70 mm² or 95 mm², ithas been confirmed that the portion of vehicle-side electric wire 3 awayfrom female terminal 21 by 100 cm is stable in temperature (or an effectof heat generated at the connecting portion of male terminal 11 andfemale terminal 21 is substantially negligible).

From the above results, it can be seen that, by setting electric wire200 to have a length of 2 m or more, an effect of heat generated at aconnecting portion of one male terminal 11 and one female terminal 21 ona connecting portion of the other male terminal 11 and the other femaleterminal 21 via the electric wire is negligible. Thus, in the presentembodiment, electric wire 200 is set to have a length of 2 m or more.Each crimp terminal 300 is connected to an end 210 of electric wire 200.Each crimp terminal 300 has a crimp portion 310 and a crimp-side flange320.

Crimp portion 310 crimps end 210 of electric wire 200.

Crimp-side flange 320 is connected to crimp portion 310. Crimp-sideflange 320 is formed flat. Crimp-side flange 320 is provided with aninsertion hole (not shown). Crimp-side flange 320 is fixed tofemale-side flange 130 by a bolt B and a nut (not shown). Bolt B isinserted into insertion hole 130 h of female-side flange 130 and theinsertion hole of crimp-side flange 320.

Adjustment member 400 can adjust contact resistance of female terminal100 and male terminal 11. Specifically, adjustment member 400 can applyan external force to each female terminal 100 to reduce each femaleterminal 100 in diameter. Adjustment member 400 includes an annular band410, a metal band 420, and an adjustment unit 430.

Annular band 410 is attached around the plurality of contact pieces 110.Annular band 410 surrounds the entire circumference of the plurality ofcontact pieces 110. Annular band 410 is made of an electrically andthermally insulating material (resin or the like). In the directionparallel to center axis A, annular band 410 is smaller in length thanslit 112S.

Metal band 420 is wrapped around annular band 410. Metal band 420 canapply an external force to the plurality of contact pieces 110 of femaleterminal 100 to reduce the plurality of contact pieces 110 in diameter.

Adjustment unit 430 can adjust a force applied by metal band 420 toclamp the plurality of contact pieces 110 (or reduce the plurality ofcontact pieces 110 in diameter). Specifically, adjustment unit 430adjusts metal band 420 in diameter to adjust the clamping force.Adjustment unit 430 has a screw capable of adjusting metal band 420 indiameter.

A method for evaluating charging connector 5 in coolability by usingevaluation jig 50 will now be described. Specifically, chargingconnector 5 is evaluated in coolability by connecting the pair of femaleterminals 100 of evaluation jig 50 to the pair of male terminals 11 ofmale connector 10. This evaluation method includes a removing step, aconnecting step, an adjusting step, and an evaluating step.

The removing step is a step of removing a portion of each tubular wall17 of male casing 15. Specifically, as shown in FIGS. 14 to 16, in theremoving step, each tubular wall 17 is partially removed to form aroundmale terminal 11 an operating space 17S allowing an operation to beperformed therein via adjustment unit 430 to adjust the external force.This partially exposes each male terminal 11. Thus, the removing stepremoves a portion other than a portion capable of suppressing a shortcircuit of male terminals 11 or male terminal 11 and other terminals 12to 14, that is, a portion of tubular wall 17 where paired tubular walls17 face each other. In the present embodiment, a portion of tubular wall17 outside male terminal 11 in a direction of an imaginary lineconnecting male terminal 11 and protective grounding terminal 12 isremoved.

The connecting step is a step of connecting the pair of female terminals100 of evaluation jig 50 to the pair of male terminals 11. In theconnecting step, in a state in which each female terminal 100 has theplurality of contact pieces 110 with annular band 410 and metal band 420attached thereto, female terminal 100 is connected to male terminal 11.As shown in FIGS. 17 and 18, in the connecting step, female terminal 100is inserted until distal end portion 112 a of each flexible piece 112contacts surface 16S of bottom wall 16 of male casing 15. FIG. 17 showsone female terminal 100 alone receiving male terminal 11.

The adjusting step is a step of adjusting a connection state of maleterminal 11 and female terminal 100. Specifically, in the adjustingstep, the external force (the clamping force by metal band 420) isadjusted by adjustment unit 430. More specifically, in the adjustingstep, the external force is adjusted by operating adjustment unit 430with an operating tool (not shown) in operating space 17S so thatcontact resistance between male terminal 11 and female terminal 100falls within a prescribed range. In this step, for example, from abovein FIG. 17, the clamping force of adjustment unit 430 is adjusted withthe operating tool.

In the adjusting step, the external force is preferably adjusted so thatthe contact resistance is 0.06 mΩ or more and 0.15 mΩ or less, morepreferably 0.08 mΩ or more and 0.1 mΩ or less.

Herein, as shown in FIG. 18, the contact resistance is measured by aresistance value between a point P1 of 4.5 mm from surface 16S of bottomwall 16 and a point P2 of 43 mm from surface 16S of bottom wall 16. Thecontact resistance may be measured with a milliohm tester or may bedetermined by a voltage drop caused when a current of 400 A is supplied.Point P2 is in a vicinity of a boundary between a region affected by astandard applied in designing male connector 10 including male terminal11 and a region unaffected thereby.

In the evaluating step, in a state with male terminal 11 and femaleterminal 100 connected together, a charging current of 400 A is suppliedfor 30 minutes, and the charging connector is evaluated in coolabilityby whether male terminal 11 and female terminal 100 have a temperatureof 90° C. or lower. Whether male terminal 11 and female terminal 100have such a temperature may be detected with a temperature sensor (notshown) provided to male terminal 11 or female terminal 100.

Thus, by using evaluation jig 50 of the present embodiment, an amount ofheat generated when charging connector 5 has a current passingtherethrough can appropriately be evaluated.

The exemplary embodiment described above is a specific example of thefollowing aspect.

An evaluation jig of the above embodiment comprises a pair of femaleterminals connectable to a pair of male terminals of a chargingconnector, and an electric wire connecting the paired female terminals,the electric wire having a cross-sectional area of 70 mm² or more and 95mm² or less and a length of 2 m or more.

The evaluation jig that comprises the electric wire having across-sectional area of 70 mm² or more and 95 mm² or less and a lengthof 2 m or more allows an appropriate evaluation of an amount of heatgenerated (or a degree at which temperature rise) at a connectingportion of a male terminal and a female terminal without beingsubstantially affected by the electric wire's heat radiationcharacteristic when a current passes (or the evaluation is made). Eachterminal can thus be designed based on a result of the evaluation.

Preferably, the electric wire is made of copper.

Furthermore, an evaluation jig comprises a pair of female terminalsconnectable to a pair of male terminals of a charging connector, and anadjustment member that can adjust contact resistance of the femaleterminal and the male terminal, wherein the female terminal can bereduced in diameter, the adjustment member includes an annular bandattached to an outer peripheral surface of the female terminal andformed in an annular shape surrounding the female terminal, a metal bandattached to an outer peripheral surface of the annular band and capableof applying an external force to the female terminal to reduce thefemale terminal in diameter, and an adjustment unit that can adjust theexternal force applied by the metal band to the female terminal, and theannular band is made of an electrically and thermally insulatingmaterial.

The evaluation jig that comprises the adjustment unit that can adjustthe external (or clamping) force applied by the metal band to the femaleterminal can adjust contact resistance between the male terminal and thefemale terminal, and furthermore, the annular band disposed between thefemale terminal and the metal band that is made of an electrically andthermally insulating material can suppress heat radiation caused at themetal band or the adjustment unit, and hence reduction in accuracy inevaluating an amount of heat generated at a connecting portion of themale terminal and the female terminal.

An evaluation method of the above embodiment is an evaluation methodperformed by connecting to a charging connector including a pair of maleterminals that can be cooled with a coolant an evaluation jig includinga pair of female terminals connectable to the pair of male terminals, byconnecting the pair of female terminals of the evaluation jig to thepair of male terminals of the charging connector, for evaluating thecharging connector in coolability, the method comprising: connecting thepair of female terminals to the pair of male terminals; adjusting aconnection state of the male terminal and the female terminal so that acontact resistance between the male terminal and the female terminal is0.06 mΩ or more and 0.15 mΩ or less; and, after the step of adjusting,evaluating the coolability depending on whether the male terminal andthe female terminal have a temperature of 90° C. or lower when acharging current of 400 A is supplied to the male terminal and thefemale terminal for 30 minutes.

In this evaluation method, contact resistance between the male terminaland the female terminal is defined to fall within a range of 0.06 mΩ ormore and 0.15 mΩ or less, and variation in evaluation results issuppressed. Therefore, the charging connector's coolability can beappropriately evaluated. Further, designing the female terminal of thecharging inlet such that the contact resistance is 0.06 mΩ or more and0.15 mΩ or less allows the male terminal and the female terminal to havea temperature of 90° C. or lower when a charging connector which obtainsa good evaluation result in the step of evaluating is used to chargepower with a charging current of 400 A supplied for 30 minutes.

Preferably, in the step of adjusting, the connection state is adjustedso that the contact resistance is 0.08 mΩ or more and 0.1 mΩ or less.

Further, an evaluation method of the above embodiment is an evaluationmethod performed by connecting to a charging connector including a pairof male terminals that can be cooled with a coolant and a bottom wallthat holds the pair of male terminals in a state in which the pair ofmale terminals are inserted therethrough an evaluation jig including apair of female terminals connectable to the pair of male terminals, byconnecting the pair of female terminals of the evaluation jig to thepair of male terminals of the charging connector, for evaluating thecharging connector in coolability, the method comprising: connecting thepair of female terminals to the pair of male terminals; and adjusting aconnection state of the male terminal and the female terminal so thatcontact resistance between the male terminal and the female terminalfalls within a prescribed range, wherein in the step of adjusting, aresistance between a point of 4.5 mm of the male terminal from a surfaceof the bottom wall and a point of 43 mm of the female terminal from thesurface of the bottom wall is measured as the contact resistance.

In this evaluation method, a measurement point for contact resistancebetween the male terminal and the female terminal is determined, and anappropriate evaluation result of the coolability can be obtained.Specifically, a measurement point on the side of the male terminal is apoint of 4.5 mm from the surface of the bottom wall. At this point, themale terminal has a sufficiently large cross-sectional area, and aneffect on the contact resistance is reduced. A measurement point on theside of the female terminal is a point of 43 mm from the surface of thebottom wall. This point is in a vicinity of a boundary of a regionaffected by a standard applied in designing the charging connectorincluding the male terminal and a region unaffected by the standard.Therefore, designing the female terminal of the charging inlet toachieve contact resistance equal to or less than that measured at thispoint suppresses the male and female terminals' temperature to be areference value or smaller when a charging connector that satisfies thestandard is used to charge power.

Preferably, the evaluation method further comprises, after the step ofadjusting, evaluating the coolability based on whether the male terminaland the female terminal have a temperature equal to or lower than 90° C.when a charging current of 400 A is supplied to the male terminal andthe female terminal for 30 minutes.

Furthermore, an evaluation jig of the above embodiment includes a pairof female terminals connectable to a pair of male terminals of acharging connector, and an adjustment member that can adjust contactresistance of the female terminal and the male terminal, wherein thefemale terminal can be reduced in diameter, and the adjustment membercan apply an external force to the female terminal to reduce the femaleterminal in diameter.

In this evaluation jig, the female terminal can be reduced in diameterand the adjustment member can apply an external force to the femaleterminal to reduce the female terminal in diameter, and contactresistance of the male terminal and the female terminal can be adjustedto fall within a prescribed range. Thus, the charging connector'scoolability can be appropriately evaluated.

Furthermore, an evaluation method of the above embodiment is a methodperformed by connecting to a charging connector including a pair of maleterminals that can be cooled with a coolant and a pair of tubular wallssurrounding each of the paired male terminals an evaluation jigincluding a pair of female terminals that can be connected to the pairof male terminals and reduced in diameter and an adjustment member thatcan apply an external force to each of the paired female terminals toreduce the female terminal in diameter, by connecting the pair of femaleterminals of the evaluation jig to the pair of male terminals of thecharging connector, for evaluating the charging connector incoolability, the method comprising: partially removing each tubular wallof the paired tubular walls to form around the male terminal anoperating space allowing an operation to be performed therein via theadjustment member to adjust the external force; connecting the pair offemale terminals to the pair of male terminals; and adjusting theexternal force in the operating space by the adjustment member so thatcontact resistance between the male terminal and the female terminalfalls within a prescribed range.

In this evaluation method, an operating space allowing an operation tobe performed therein to adjust external force is formed around a maleterminal, and contact resistance can be adjusted in a state with theevaluation jig having a female terminal connected to the male terminal.

In the step of removing, the tubular wall preferably has removed aportion other than a portion at which the paired tubular walls face eachother.

This suppresses short circuit of the male terminals.

Further, the adjustment member may include an annular band that isattached to an outer peripheral surface of the female terminal andformed in an annular shape surrounding the female terminal, a metal bandthat is attached to an outer peripheral surface of the annular band andcan apply a force to the female terminal to reduce the female terminalin diameter, and an adjustment unit that can adjust a force applied bythe metal band to clamp the female terminal, and the annular band may bemade of an electrically and thermally insulating material. In this case,preferably, in the step of connecting, the pair of female terminals isconnected to the pair of male terminals in a state with the annular andmetal bands attached to each female terminal, and in the step ofadjusting, the force applied by the metal band to clamp the femaleterminal is adjusted in the operating space.

Furthermore, an evaluation jig of the above embodiment comprises afemale terminal connectable to a male terminal of a charging connector,the female terminal including a plurality of contact pieces which caneach contact the male terminal and are spaced about a center axis, and asupport portion to support the plurality of contact pieces, theplurality of contact pieces each having a flexible piece having a shapeextending from the support portion in a direction parallel to the centeraxis, and a contact portion protruding toward the center axis from aninner surface of the flexible piece, the flexible piece forming aportion of a cylinder having the center axis, the flexible piece havinga length equal to or larger than twice an outer diameter of the cylinderin a direction parallel to the center axis, the flexible piece beingelastically deformable so that the flexible piece has a distal endportion to be displaceable in a radial direction of the cylinderrelative to a proximal end portion of the flexible piece serving as aconnecting portion of the flexible piece and the support portion, thecontact portion having a shape curved so as to protrude inward in theradial direction.

In this evaluation jig, the flexible piece that has a length equal to orgreater than twice the outer diameter of the cylinder in the directionparallel to the center axis is each less plastically deformable when thefemale terminal is repeatedly connected to and pulled out of the maleterminal, and furthermore, each contact portion having a shape curved soas to protrude inward in the radial direction reliably contacts the maleterminal. This allows prescribed contact resistance to be reliablyreproduced and the charging connector's coolability to be evaluatedappropriately.

Preferably, the contact portion has a shape extending in a directionparallel to the center axis.

Thus, even when the female terminal is connected to the male terminal ina state with the female terminal's center axis inclined relative to themale terminal's center axis, the female terminal is guided to have aposture so that the center axes match each other.

Preferably, the flexible piece has a protruding portion protruding fromthe contact portion in a direction parallel to the center axis away fromthe support portion.

Preferably, the flexible piece and the contact portion have a boundaryportion therebetween in a curved shape.

In this case, the contact portion preferably has an apex smaller incurvature than the boundary portion.

Furthermore, preferably, the flexible piece has a facing surface facinga flexible piece adjacent to the flexible piece of interest in thecircumferential direction of the cylinder, and any pair of such facingsurfaces facing each other in the circumferential direction are parallelto each other.

It should be understood that the presently disclosed embodiments areillustrative and not restrictive in any respect. The scope of thepresent invention is defined by the terms of the claims and intended toencompass any modifications within a meaning and scope equivalent to theterms of the claims.

What is claimed is:
 1. An evaluation method for evaluating a chargingconnector in coolability by connecting an evaluation jig to the chargingconnector, the charging connector including a pair of male terminalscoolable with a coolant, the evaluation jig including a pair of femaleterminals connectable to the pair of male terminals, the pair of femaleterminals being connected to the pair of male terminals in evaluatingthe charging connector in coolability, the method comprising: connectingthe pair of female terminals to the pair of male terminals; adjusting aconnection state between the male terminal and the female terminal suchthat contact resistance between the male terminal and the femaleterminal is 0.06 mΩ or more and 0.15 mΩ or less; and after the adjustingthe connection state, evaluating the coolability depending on whetherthe male terminal and the female terminal have a temperature of 90° C.or lower when a charging current of 400 A is supplied to the maleterminal and the female terminal for 30 minutes.
 2. The evaluationmethod according to claim 1, wherein in the adjusting the connectionstate, the connection state is adjusted so that the contact resistanceis 0.08 mΩ or more and 0.1 mΩ or less.